1. Field of the Invention
The present invention relates to a camera provided with an automatic focusing device which automatically adjusts the focusing of an object to be photographed, and more particularly it pertains to such a camera with an automatic focusing device comprising an objective lens driving means and a selection means for alternatively selecting a first condition for allowing the objective lens driving even after the detection of an in-focus condition and a second condition for inhibiting the lens driving once an in-focus condition was allowed. While a switching means is closed the lens driving means drives the objective lens in accordance with the judgment of focusing of the objective lens on an object to be photographed.
2. Description of the Prior Art
Conventional cameras are arranged such that the switching means and the selection means are operated by different members. For example, a distance measuring or focusing actuation switch is provided as the switching means and the automatic focusing device always determines in-focus or out-of-focus measuring of the camera-to-object distance and drives the objective lens in accordance with the results of the determination such that the object is within an in-focus range. This is the first condition. In the case, the user wishes to stop the objective lens once and an in-focus condition is attained, e.g. when the user wishes to take a picture of an object locating the latter at a position other than the central portion of th scene to be photographed after the focusing has been adjusted on the object with the image of the object being registered with the focusing area mark or frame at the center of the viewfinder field, a selector means such as a focus-lock switch is operated to change-over the focusing device to the second condition. (See for example Japanese laid-open patent applications with laid-open Nos. 50-99729 and 58-8727)
When the objective lens is driven by an electric means, e.g. an electric motor, the driving requires a considerable amount of current of several ampere. Accordingly, it may be desirable to save the electric energy consumption that the automatic focusing device is normally deenergized and the switching member is closed to actuate the automatic focusing device when the focusing should be adjusted. However, the conventional cameras required operation of both the switching member and the selection member respectively for the focusing and it takes much electrical power for the focusing.